Behavioural Effects of Early Focal Damage to Prefrontal Cortex
Anderson et al. (2007) report a case of a 14 month boy (PF1) who sustained damage to his right inferior dorsolateral prefrontal cortex due to resection of a vascular malformation on day 3 of life. After a successful surgery he exhibit normal behaviour and reached developmental milestones at a normal rate. Also, his performance on various clinical tests was normal, as well as his social and communication skills as rated by his mother. Compared to a sample of healthy controls PF1 was impaired significantly in the regulation of emotion and engagement of attention, specifically in unstructured conditions.
In particular, Anderson et al. (2007) report that:
markedly high positive affectivity and low restraint
relative to his peers. This was particularly evident
in his intense and positive affective expressions
during free-flowing interactions, his unrestrained
approach of desirable but prohibited stimuli, and to
a lesser extent in his mildly atypical levels of anger
and resistance when physically restrained. Faced
with problem-solving tasks, when most of his peers
displayed affectively neutral expressions and
focused on finding the solutions, PF1 initially
responded with strong and under-regulated positive
emotion that interfered with attentional engagement
on the task at hand.
According to the writers the results of the study provide useful information about the impact that early damage in the prefrontal cortex may have on emotional and cognitive behaviour. I’m looking forward to their future reports on this particular case as the boy grows up.
Anderson SW, Aksan N, Kochanska G, Damasio H, Wisnowski J, & Afifi A (2007). The earliest behavioral expression of focal damage to human prefrontal cortex. Cortex; a journal devoted to the study of the nervous system and behavior, 43 (6), 806-16 PMID: 17710831